The present invention relates to mortar type munitions and more particularly pertains no structural improvement therein for substantially improving the water resistance and imperviousness thereof without imparting or contributing to any degrading residue.
In the field of mortar munitions and such, it has been the general practice to encase or provide barriers, as are employed in prior art devices, to increase the water resistance of the primer and cartridge of a mortar shell. In general, water or vapor can and does enter a mortar shell through the flash holes to the cartridge or by way of the primer and tunnel. Water resistance of these shells has been improved by physically encasing the ignition cartridge in a plastic wrapping or vapor barrier and by positively sealing the primer structure to the tail assembly. Another technique employed is to provide an external plastic vapor barrier around the outer surface of the mortar and closing off the flash holes. This latter solution necessitates the use of special adhesives wich although satisfactory from a bonding viewpoint, exhibit extremely poor residue properties. On the other hand, even though, only a minimal proportion of residue is generated outside of the mortar, water is still permitted to enter the flash holes. In any event these techniques have proved unsatisfactory while the present invention fills this need and provides a satisfactory solution.